Latch module and an appliance using the same

ABSTRACT

A latch module for controlling an opening and a closing of a door of an appliance includes a latch, a spring that applies an elastic force to the latch, a motor; and a cam that contacts a contact surface of the latch and is coupled to the motor to drive the cam to pivot the latch. The cam includes a first radius, a second radius, and a third radius in a circumferential direction at an outer circumference of the cam. The latch is positioned at a first basic position when the first radius of the cam contacts the contact surface of the latch, positioned at a second basic position when the second radius of the cam contacts the contact surface of the latch, and positioned at a third basic position when the third radius of the cam contacts the contact surface of the latch.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2018-0044151 filed on Apr. 16, 2018, the disclosureof which is incorporated herein by reference in its entirety.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates to a latch module having an automaticopening function and a secure lock function incorporated therewith, amethod of controlling such latch module, and a cooking device applyingsuch latch module.

Background

A cooking device such as an oven or a microwave oven includes arectangular parallelepiped appearance. The cooking device includes aninner cooking chamber having an open front thereof, and a door in frontof the cooking chamber.

The door may be opened in various ways. For example, a hinge-connecteddoor connected by a hinge method rotates about a rotational shaft. Thehinge type door may have a handle or groove that the user may grip.

A cooking device may have an automatic opening function of a doorthereof to improve the quality of use. Of course, even if the automaticopening function of the door is applied, for convenience of the user,the door may be designed to be manually opened or closed.

Further, a self-cleaning function is added to the cooking device so thatthe cooking chamber is easily cleaned. The self-cleaning functionenables heating the inside of the cooking chamber to a high temperatureso that food attached to an inner wall of the cooking chamber is burned,or treating the food attached to the inner wall of the cooking chamberwith high-temperature steam, so that the food is softened andconveniently removed during cleaning. In order to prevent a safetyaccident, the door of the cooking device may be securely closed during aself-cleaning operation.

U.S. Pat. No. 7,726,294 and US Patent Publication No. 2007/0296224disclose an operating structure of a hook for maintaining a door in asecurely closed state during the self-cleaning operation. By rotating adrive such as a motor and the like, and applying a link structure, whenthe door needs to be maintained in a securely closed state, the hook isoperated by the drive so that the hook is engaged with the door, andwhen the door no longer needs to be maintained in the securely closedstate, the hook is operated again by the drive so that the hook isreleased from the door.

With the operating structure of a hook described above, after the hookis released from the door, a door lock device enables closing the doorand does not enable automatically opening the door. That is, the doorlock device has no means for automatically opening the door.

A secure (secure lock, self-cleaning lock) device that serves tosecurely lock the door during the self-cleaning operation and anautomatic opening (auto door open) device that serves to automaticallyopen the door may be applied individually. That is, U.S. Pat. No.7,726,294 and US Patent Publication No. 2007/0296224 provide a drive (amotor) that provides power and a power transmission structure tosecurely lock the door, and another drive (another motor) that providespower and another power transmission structure to automatically open thedoor.

SUMMARY

It is not easy to incorporate a secure lock function of a door forself-cleaning with a separate automatic opening function of the doorwhen a manual opening and closing function of the door needs to beimplemented as well.

However, when new functions are added, the modules for implementing thefunctions are added individually, thereby increasing the number ofcomponents and production costs, as well as increasing the occupiedvolume in the cooking device, thereby decreasing the volume of thecooking chamber.

It is desirable to have a module incorporated with various functions.However, in situations described above, when the module is incorporatedwith a safety function for preventing accidents, the function forpreventing the accidents needs to be robust and reliable.

Accordingly, a door control module capable of incorporating allfunctions as well as minimizing the number of parts, and having a safetyfunction for preventing an accident is highly desirable.

On the other hand, when the door control module is incorporated withvarious functions, the drive control also becomes complicated, and moreswitches for controlling the parts that drive the door control modulemay need to be installed. However, an increase in the number ofinstalled switches not only increases an occupied volume in the doorcontrol module, but also raises production costs.

Further, when the functions are incorporated, initializing the doorcontrol module is required when the cooking device is initially suppliedwith power. However, if the door control module does not have a properinitialization structure and operated, for example, the door mayaccidentally open automatically during initialization of the doorcontrol module, and the user may think that the cooking device isoperating incorrectly or the cooking device has failed. Therefore, thedoor control module should not automatically open the door when the doorcontrol module is initialized.

The present disclosure solves the above-mentioned problems. The presentdisclosure provides a latch module that implements a manual lockfunction of a door and a secure lock function of a door forself-cleaning operation of a cooking chamber with one latch and acooking device applying such latch module.

The present disclosure further provides a latch module that implements amanually opening and closing function of a door and an automatic openingfunction of a door and a secure lock function of a door by operatingwith one latch and a cooking device applying such latch module.

The present disclosure also provides a latch module that implements amanually opening and closing function of a door and an automatic openingfunction of a door and a secure lock function of the door by operatingwith one latch with one drive source and one power transmissionstructure, and a cooking device applying such latch module.

The present disclosure also provides a latch module that implements asecure lock and unlock function of a door by means of a kinematicinterference between the two components while one latch implements thetwo functions and a cooking device applying such latch module.

The present disclosure also provides a structure capable of accuratelycontrolling a latch module while minimizing the number of switches to beinstalled, a method of controlling such latch module, and a cookingdevice applying such latch module.

The present disclosure also provides a structure of a latch module inwhich a user may not mistakenly consider the operation of the cookingdevice as malfunctioning or failure at the beginning of the driving ofthe cooking device and a method of controlling such latch module.

The present disclosure may be applied to an appliance such as a cookingdevice including a main body having a cooking chamber (a cavity), a doorthat opens and closes an open front of the cooking chamber, and anopening or closing rotational shaft as a center of rotation of openingand closing a movement of the door.

The opening and closing rotational shaft rotatably connects the doorwith respect to the main body about a horizontal rotational shaftextending in a left-right direction and disposed at a front lowerportion of the main body. Accordingly, the door may have a pull-downstructure in which the door is rotated forward about the rotationalshaft and descends and is opened.

The door may be connected to the main body via a hinge module includingthe opening and closing rotational shaft. The hinge module may apply anelastic force so as to move the door in an opening direction in a rangeof initial opening angle and may apply an elastic force the door in aclosing direction thereof in a range in which an opening angle of thedoor exceeds the initial opening angle.

The door may be opened by its own weight at the initial opening angle. Adamper starts to damp an opening speed of the door at a dampingbeginning angle greater than the initial opening angle. The openingspeed is controlled until the door is opened to a completely openedangle so that the door is opened slowly.

The cooking device may have a self-cleaning function of raising atemperature inside of the cooking chamber to a high temperature.Accordingly, the door is prevented from being opened in advance when thedoor is securely locked to perform the self-cleaning function.

The cooking device may further apply a structure that automaticallyopens the door by means of command input by a user. Generally, the dooralso may be manually opened and closed.

According to the present disclosure, all of these functions areimplemented by one latch module. The latch module may be installed onthe main body and a rear upper portion of the door may have a pin whichis an engaged structure that is engaged with or released from a latch ofthe latch module. The position at which the latch may move may include afirst basic position, a second basic position, and a third basicposition.

Each of the first basic position and the third basic position may be aposition in which the latch is engaged with the engaging structure so asto maintain a state in which the door is closed.

The second basic position may be a position in which the latch is notengaged with the engaging structure.

The first basic position may be a position in which, when an externalforce is applied to the door in a direction of opening the door, thelatch is released from the engaging structure so that the door isopened, while the third basic position may be a position in which, evenif the external force is applied to the door in a direction of openingthe door, a state in which the latch is engaged with the engagingstructure is maintained.

The latch may be moved to at least one position of the three positionsby the controller. In other words, the controller may control theposition of the latch.

The hinge module may apply a force in a direction of opening the door ata position in which the door is closed. Thus, when the latch is in thesecond basic position, the door may be opened by the force of the hingemodule.

In order to solve the above-described problems, according to the presentdisclosure, the latch module may include a bracket as a base of thelatch module; a latch installed in the bracket rotatable about a pivotshaft and having a hook engaged with the pin, an elastic body that movesthe latch to rotate in a first direction; a drive that provides a powerfor rotating the latch in a second direction which is an opposite to thefirst direction using a force greater than an elastic force of theelastic body; and a power transmission that transmits the power of thedrive to the latch.

The hook is opened toward the first direction, and an engaging surfacethat is engaged with the pin is provided inside of the hook. An inclinedinsertion surface may be provided on a surface opposed to the engagingsurface of the hook.

The engaging surface includes a disengaged inclined surface arrangedcloser to the first direction and a secure lock surface arranged closerto the second direction. The two surfaces are connected to each othervia a soft curved surface so that a sliding of a pin about the twosurfaces is smooth.

Depending on a rotation position of the latch, the portions of theengaging surface in contact with the pin are varied. The pin contactsthe disengaged inclined surface or contacts the secure lock surfacedepending on the rotation position of the latch.

In a general state, that is, in a manual lock state where the user maymanually open and close the door, a rear surface of the pin of the doorcontacts the disengaged inclined surface when the door is closed. Inorder to allow the user to manually open the door, when the latch isrotated so as to be in a state in which the disengaged inclined surfacecontacts the pin, the disengaged inclined surface has a surface inclinedin the opening direction of the door toward the first direction. Whenthe user pulls the door in an opening direction thereof, the latch mayrotate in the second direction by using a force in which the pin pushesthe disengaged inclined surface, which is greater than the elasticforce, and thereby the door may be manually opened.

When the user closes the door in a state where the door is opened, thesurface of the pin of the door contacts the inclined insertion surface.In order for the user to manually close the door, when the latch rotatesso as to be in the state in which the inclined insertion surfacecontacts the pin, the inclined insertion surface has a surface inclinedin the closing direction of the door toward the first direction.

The inclined insertion surface may be provided not only in a positionrange opposed to the disengaged inclined surface but also in a positionrange opposed to the secure lock surface. It is possible to close theopened door regardless of whether the latch is in any position (themanual lock position and the secure lock position).

In a general state, the elastic body is involved in the operation of thelatch for a manual opening and closing operation.

In a completely locked state where the user does not manually open thedoor for self-cleaning and the like, that is, in the secure lock state,the pin of the door contacts the secure lock surface. The latch isfurther rotated in the first direction than in the manual lock state andthe pin of the door is relatively positioned deeply inward the hook(actually, the pin remains its position and the hook is furtherrotated).

In order for the hook to completely securely lock the door, the securelock surface may have a surface inclined in the closing direction of thedoor toward the first direction. Then, when the user pulls the door, aforce applied by the pin of the door to the hook further rotates thehook in the first direction. That is, the more the user opens the door,the deeper the pin is positioned deeply inward the hook. In other words,the more the user opens the door, the more the hook securely locks thepin.

Similar result is obtained if the secure look surface has a surfaceperpendicular to the opening direction of the door. That is, even if theuser opens the door, such force does not lead to the rotation of thelatch.

An elasticity of the elastic body contributes to rotate the latch from amanual lock position to a secure lock position.

As described above, according to the present disclosure, the engagingsurface of the hook of the latch for opening and closing the door has aportion capable of manually opening and closing the door and a completesecure lock portion. It is possible to determine which one of the twoportions contacts the pin of the door depending on a rotationdisplacement of the latch so that both the manual lock state and thesecure lock state of the door may be implemented by one latch.

The automatic opening operation of the door and the secure lockoperation of the door may be implemented with one latch, one drive andpower transmission that drive the latch.

The power transmission is a cam in contact with a contact surfaceprovided on the side of the latch. A center of rotation of the cam maybe disposed in adjacent to a first direction, than a side of the latchto which the cam contacts. It is possible to determine a position of thelatch by changing the radius of the cam that contacts the latchdepending on the rotational displacement of the cam.

As the elastic body elastically supports the latch so as to rotate inthe first direction and the center of rotation of the cam is disposed inadjacent to the first direction than the latch, a degree in which thelatch may move in the first direction may be determined depending on theradius of the cam that contacts the latch. Of course, even in thisstate, the latch may move in the second direction by a force greaterthan the elastic force of the elastic body. When the force greater thanthe elastic force of the elastic body disappears, the latch is rotatedand returned again by the elastic body to the position in contact withthe cam in the first direction.

A combination of the elastic body that elastically forces the latch inthe first direction and the cam disposed in adjacent to the firstdirection than the latch may simply enable a basic position of the latchto be adjusted by adjusting a radius of the cam in contact with thelatch. Adjusting the basic positions of the latch may be a method ofdetermining which one of the disengaged inclined surface and the securelock surface in the engaged surface of the hook of the latch contactsthe pin of the door.

The cam may include the radiuses having at least three differentradiuses in a circumferential direction thereof at the outercircumference thereof. The first radius enables the latch to be in thefirst basic position and the second radius enables the latch to be inthe second basic position, and the third radius enables the latch to bein the third basic position.

When the latch is moved in a second direction in the first basicposition, the latch may reach the second basic position. When the latchis moved in a first direction in the first basic position, the latch mayreach the third basic position.

The first radius as a reference enables a latch to be in a general basicposition, that is, a position where the user may manually open and closethe door (a manual lock position). The pin of the door contacts thedisengaged inclined surface of the hook of the latch at a position wherethe first radius contacts the contact surface of the latch.

The second radius has a radius greater than the first radius. The secondradius is connected to the first radius via a connecting surface havinga smooth curved surface. Therefore, when the cam rotates in a firstrotational direction such that a contact portion of the cam and thelatch is moved from the first radius to the second radius, a basicposition of the latch further moves in the second direction. When thesecond radius contacts the latch, the hook of the latch moves to theopen position and may no longer be engaged with the pin of the door.That is, the pin is relatively away from the hook.

Accordingly, when the latch in contact with the first radius contactsthe second radius as the cam rotates, the door is moved by the elasticforce by the hinge module so that the door is opened to the initialopening angle and the door is completely opened by the weight of thedoor itself.

The third radius has a radius less than the first radius. The thirdradius is connected to the first radius via a connection surface havingthe smooth curved surface. Therefore, when the cam rotates in a secondrotational direction (a direction opposite to the first rotationaldirection) so that the contact portion of the cam the latch is movedfrom the first radius to the third radius, the basic position of thelatch is further moved in the first direction to move to the secure lockposition. When the third radius contacts the latch, the hook is engagedwith the pin of the door deeply inward. That is, the pin of the doorcontacts the secure lock surface of the hook of the latch.

According to the present disclosure, the operation of moving the latchfrom the first basic position to the third basic position may be made bythe elastic body. However, if the latch is engaged with the first basicposition due to an unexpected state, the elastic force applied by theelastic body in the first direction may not enable the latch to movefrom the first basic position to the third basic position.

According to the present disclosure, while the cam rotates from thefirst mode to the third mode, the surface of the cam and the latch arekinematically interfered with each other, and power of the drive istransmitted to the latch so as be applied in a direction of moving fromthe first basic position to the third basic position.

Further, due to the kinematic interference of the cam and the latch whenthe cam is in a third mode and the latch is also in the third basicposition, the present disclosure provides a structure in which the latchis prevented from deviating from the third basic position toward thefirst basic position.

To this end, according to the present disclosure, the latch furtherprovides an extension that may be kinematically interfered with the cam.The extension has an sub-contact surface that approaches the cam as thelatch moves in the second direction and is away from the cam as thelatch moves in the first direction. Meanwhile, the contact surface 55approaches the cam 70 as the latch 50 moves in the first direction andis away from the cam 70 as the latch 50 moves in the second direction.

The cam 70 may transmit the power of the drive to the latch by thecontact surface 55 so that the latch moves in the second direction. Thecam 70 may transmit the power of the drive to the latch by thesub-contact surface 59 so that the latch moves in the first direction.The latch may be prevented from moving in the second direction in astate where the sub-contact surface is interfered with the cam 70.

In the first mode where the first radius of the cam contacts the contactsurface of the latch so that the latch is in the first basic position(the manual lock state), the extension may not disturb the manualopening and closing rotation of the latch.

To this end, the cam surface that faces the sub-contact surface when thecam is in the first mode may have a radius so that a movement for thesub-contact surface to approach the cam surface is allowed even if thelatch is moved from the first basic position to the second basicposition.

In other words, a distance between a position of the sub-contact surfaceand a center of rotation of the cam while the cam is in the first modeand the latch is in the first basic position may be greater than aradius of the cam surface in contact with the sub-contact surface whenthe first radius of the cam contacts the contact surface of the latch. Adistance between a position of the sub-contact surface and the center ofrotation of the cam while the cam is in the first mode and the latch isin the second basic position may be equal to or greater than a radius ofthe cam surface that faces the sub-contact surface while the firstradius of the cam contacts the contact surface of the latch.

In the first mode where the first radius of the cam contacts the contactsurface of the latch, the cam surface that faces the sub-contact surfacemay be the first radius, the third radius or the connecting surface thatconnects the first radius and the third radius.

In order for the latch to be moved by the cam from the first basicposition to the second basic position (the automatic opening position),when the cam rotates in the first rotational direction from the positionwhen the cam is in the first mode to the position when the cam is in thesecond mode, the extension moves in the direction of approaching thecam. In this step, the extension may not contact the cam or may not beinterfered with the cam.

While a contact point of the cam and the contact surface of the latch ismoved from the first radius to the second radius as the cam rotates, thesub-contact surface is not interfered with the surface of the cam.

In a second state where the second radius of the cam contacts thecontact surface of the latch, the sub-contact surface may face the firstradius of the cam and the sub-contact surface may not contact thesurface of the cam.

A distance between a position of the sub-contact surface and the centerof rotation 7 of the cam while the latch is in the second basic positionmay be equal to or greater than a radius of the cam surface that facesthe sub-contact surface while the second radius 7 of the cam contactsthe contact surface of the latch.

In order for the latch to be moved from the first basic position to thethird basic position (the secure lock position), while the cam rotatesin the second rotational direction from the position when the cam is inthe first mode to the position when the cam is in the third mode, whenthe latch is not smoothly moved in the first direction in spite of aforce of applying the elasticity of the elastic body, the cam may forcethe latch to move to the first direction by interfering the cam with theextension of the latch.

To this end, while the contact point of the cam and the contact surfaceof the latch is moved from the first radius to the third radius as thecam rotates, the radius of the surface of the cam that faces thesub-contact surface may be set to exceed the distance between theposition of the sub-contact surface and the center of rotation of thecam when the latch is in the first basic position.

The radius of the cam surface that faces the sub-contact surface whenthe third radius of the cam contacts the contact surface of the latchmay be greater than the distance between the position of the sub-contactsurface and the center of rotation of the cam when the latch is in thefirst basic position.

Even if the latch is stopped, the cam may forcedly push the latch tomove the latch.

The cam surface that faces the sub-contact surface may be the secondradius when the third radius of the cam contacts the contact surface ofthe latch.

The radius of the cam surface that faces the sub-contact surface whenthe third radius of the cam contacts the contact surface of the latchmay be substantially equal to the distance between the position of thesub-contact surface and the center of rotation of the cam when the latchis in the third basic position, then the latch is fundamentallyprevented from being rotated in the second direction by an unexpectedexternal force when the latch is in the secure lock position due to theinterference between the sub-contact surface and the cam.

If the latch position adjusting profile of the cam may be designed sothat the second radius is disposed at one side of the first radius (acontact surface for manual lock) and the third radius is disposed at theother side of the first radius and the cam may be rotated in onedirection or rotated in the other direction, the position of the latchmay be simply adjusted. In order to implement the adjustment of theposition of the latch more simply, the drive may be a motor rotatable inboth directions. More simply, the cam may be directly connected to arotational shaft of the motor.

According to the present disclosure, both the operations of theautomatic opening and the complete secure lock of the door areimplemented with one latch, which is determined by the basic position ofthe latch. The basic position of the latch may be determined by the camand the cam may be controlled by a controller.

If the cam is only rotatable in one direction, the latch may contact thecam in an order of the first radius→the second radius→the thirdradius→the first radius, or in an order of the first radius→the thirdradius→the second radius→the first radius.

If the latch contacts the cam in the order of the first radius→thesecond radius→the third radius→the first radius, the door may beautomatically opened before the secure lock of the door, it would bedifficult to implement the secure lock function of the door. On theother hand, if the latch contacts the cam in the order of the firstradius→the third radius→the second radius→the first radius, the door maybe opened by automatic opening after carrying out the secure lockfunction of the door. Therefore, if the motor rotatable in one directiononly is used, the latch is installed such that the motor rotates in adirection in which the latch may contact the cam in the order of thefirst radius→the third radius→the second radius→the first radius.

The rotational displacement of the cam may be controlled by pressing orreleasing the switches installed around the cam as the cam rotates. Whenthe button of the switch is pressed, the switch may be turned on. Whenthe button of the switch is released, the switch may be turned off.

Basically, in order to determine a rotational displacement of the cambased on the three basic positions of the latch (the manual lockposition as the position of the latch in a state in which the firstradius of the cam contacts the contact surface of the latch, the openingposition as the position of the latch in a state in which the secondradius of the cam contacts the contact surface of the latch, and thesecure lock position as the position of the latch in a state in whichthe third radius of the cam contacts the contact surface of the latch),three switches may be installed in the positions, respectively, and apressing boss that presses the switch may be provided in the cam. Thefirst radius contacts the latch when the first switch is pressed and thesecond radius contacts the latch when the second switch is pressed andthe third radius contacts the latch when the third switch is pressed.Then, the basic position of the latch may be adjusted through a controlthat the motor continues to rotate while no switch is pressed, and therotation is stopped when the switch is pressed.

It is also possible to control the three basic positions of the latch byusing the two switches. The latch module may further include a firstswitch and a second switch installed at the bracket.

The cam may implement a first mode in which both the first switch andthe second switch are pressed, a second mode in which the first switchis pressed and the second switch is not pressed, the third mode in whichthe second switch is pressed and the first switch is not pressed, andthe fourth mode in which both the first switch and the second switch arenot pressed depending on a rotation position of the cam.

The cam may further include a switch pressing profile capable ofimplementing the four modes, separate from the latch position adjustingprofile. In other words, the cam may include the latch positionadjusting profile and the switch pressing profile and the latch positionadjusting profile and the switch pressing profile may be providedseparately.

When the cam is rotated so that any one mode (first selected mode) ofthe first to fourth modes is implemented by the switch pressing profile,the first radius may contact the latch. When the cam is rotated so thatthe switch pressing profile is in another mode (second selected mode) ofthe first to fourth modes, the second raids may contact the latch. Whenthe cam is rotated so that the switch press profile is in yet anothermode (third selected mode) of the first to fourth modes, the thirdradius may contact the latch. The other mode of the first to fourthmodes may be the fourth selected mode. The first selected mode may bethe first mode, the second selected mode may be the second mode, thethird selected mode may be the third mode, and the fourth selected modemay be the fourth mode.

The first switch and the second switch may be disposed at substantiallythe same distance from the center of rotation of the cam. The switchpressing profile may include a first pressing boss that presses thefirst switch or the second switch or does not press both the firstswitch and the second switch depending on the rotation position of thecam, and a second pressing boss that presses the first switch or thesecond switch or does not press both the first switch and the secondswitch depending on the rotation position of the cam.

The cam may be in a range in the first mode in which the first pressingboss and the second pressing boss press the first switch and the secondswitch at the same time, respectively, or a range in the second mode inwhich the second pressing boss presses the first switch and the firstpressing boss does not press the second switch, and a range in the thirdmode in which the first pressing boss presses the second switch and thesecond pressing boss does not press the first switch, and a range in thefourth mode in which the first pressing boss and the second pressingboss do not both the first switch and the second switch depending on therotation angle thereof.

The button of the first switch and the button of the second switch havea predetermined angle with respect to the center of rotation of the cam.The first pressing boss and the second pressing boss may also have apredetermined angle with respect to the center of rotation of the cam.The angle may be less than 180° such that the two switches are notarranged on the same straight line passing through the center ofrotation of the cam and the two pressing bosses are not arranged on thesame straight line passing through the center of rotation of the cam.Preferably, the angle may be 90° or more or less than 180° or may havean obtuse angle. More preferably, the angle may be about 120°.

In the rotation range (the range in the first mode) of the cam whereboth the first switch and the second switch are pressed, the firstradius may contact the latch. In the rotation range (the range in thesecond mode) of the cam in which the first switch is pressed and thesecond switch is not pressed, the second radius may contact the latch.In the rotation range (the range in the third mode) of the cam in whichthe first switch is not pressed and the second switch is pressed, thethird radius may contact the latch.

The latch module may be controlled by a controller controlling theoperation of automatically opening the door, controlling the operationof securely locking the door, and controlling the operation of securelyunlocking the door.

Controlling the operation of automatically opening the door is performedby rotating the cam in the first rotational direction in the firstselected mode of the above modes to change the cam to the secondselected mode so as to stop the rotation of the cam, and by rotating thecam in the second rotational direction which is an opposite direction ofthe first rotational direction in the second selected mode to return thecam to the first selected mode so as to stop the rotation of the cam.

Controlling the operation of securely locking the door is performed byrotating the cam in the second rotational direction in the firstselected mode to change the cam in the third selected mode to stop therotation of the cam, so that the door is securely locked, therebypreventing the door being manually opened by the user.

Controlling the operation of releasing the door from the securely lockedstate is performed by rotating the cam in the first rotational directionin the third selected mode to change the cam in the first selected modeso as to stop the rotation of the cam, so that the door is returned tothe state where the secure lock of the door is released and the door ismanually opened and closed.

According to the present disclosure, a method of controlling the latchmodule further includes a position search and a sequence of aninitialization control of the cam of the latch module. The search andinitialization control may be executed when the cam is in the fourthselected mode in the initial drive of the latch module.

First, the cam is rotated in the second rotational direction. Accordingto the present disclosure, when the initial search drive step ofrotating the cam in the second direction is performed in the fourthmode, an error that the door is opened may not occur. Specifically,after the initial search drive step, the cam is changed from the fourthselected mode (the fourth mode) to the first selected mode (the firstmode) or to the third selected mode (the third mode).

When the cam is changed from the fourth selected mode (the fourth mode)to the first selected mode (the first mode), the drive of the cam isterminated.

When the cam is changed from the fourth selected mode (the fourth mode)to the third selected mode (the third mode), the cam is rotated in thefirst rotational direction. Then, the cam is changed to the firstselected mode (the first mode) via the fourth selected mode (the fourthmode). When the first mode is thus set, the drive of the cam isterminated.

While the user uses the cooking device, the cam may not be in the secondselected mode (the second mode) during the initial search drive step.However, just after manufacturing the product, the cam may be in thesecond mode during the initial search drive step, for just one chance.In this case, during the initial search drive step, after the cam ischanged to the second selected mode, the cam is further rotated in thesecond rotational direction, and the cam is changed to the firstselected mode (the first mode), the drive of the cam may be terminated.

The present disclosure further provides a cooking device to which thelatch module and the method of controlling such latch module areapplied. Further, the present disclosure may be applied not only to thecooking device, but also to an appliance including a main body having acavity and a door that opens and closes such main body.

According to the present disclosure, a structure of the latch moduleapplied to a cooking device may implement a manual lock function of thedoor and a secure lock function of a door for an operation ofself-cleaning by one latch.

Further, according to the present disclosure, the structure of the latchmodule may implement an automatic opening function of a door and asecure lock function of a door while one latch, one drive, and one powertransmission are applied.

Further, according to the present disclosure, in the structure of thelatch module, it is possible to manually open and close the door by anelastic body, and also to perform a secure lock of the door by theelastic body. In addition, an interference structure of the latch andthe cam complements a secure lock function of the elastic body.Therefore, even if abnormality occurs during operation of the elasticbody, an operation of securely locking the door may be made by the cam.

Further, according to the present disclosure, the structure of the latchmodule may prevent the latch in the secure lock state from beingreleased by an unexpected external force due to the interference betweenthe cam and the latch. Therefore, all operations may be implemented byone latch and one cam.

Further, according to the present disclosure, in the structure of thelatch module, the automatic opening of the door and secure lock of thedoor may be controlled through the two switches and a simple control.

Further, according to the present disclosure, a method of controllingthe latch module may only perform the initial position search of the camand the latch with a simple control algorithm and the door may not beopened unintentionally in the initial search step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a cooking device including a latch moduleaccording to an embodiment of the invention.

FIG. 2 is a transparent perspective view of a hinge module that connectsa door and a main body of a cooking device according to an embodiment ofthe invention.

FIG. 3 is a side view of FIG. 2.

FIG. 4 is a perspective view of a latch module according to anembodiment of the invention.

FIG. 5 is an exploded perspective view of the latch module of FIG. 4.

FIG. 6 is a top view of a latch of the latch module of FIG. 4.

FIG. 7 is a plan view of a cam of the latch module of FIG. 4.

FIG. 8 is a graph of a radius of the cam depending on an angularposition of the cam of FIG. 7.

FIG. 9(a) is a bottom view of a cooking device having the latch moduleof FIG. 4, and FIG. 9(b) is a plan view of the cam and a part of thelatch in contact with the cam, both representing a state where the latchis engaged with a pin of a door while the latch is in a manual lockposition.

FIG. 10(a) is the bottom view of the cooking device, and FIG. 10(b) isthe plan view of the cam and the part of the latch in contact with thecam, both representing a state where the latch module is operated andthe latch moves to the open position.

FIG. 11(a) is the bottom view of the cooking device, and FIG. 11(b) isthe plan view of the cam and the part of the latch in contact with thecam, both representing a state where the latch is disengaged from thepin of the door and the door is opened to an initial open angle.

FIG. 12(a) is the bottom view of the cooking device, and FIG. 12(b) isthe plan view of the cam and the part of the latch in contact with thecam, both representing a state where the latch module operates and thelatch is in the manual lock position while the latch is disengaged fromthe pin of the door.

FIG. 13(a) is the bottom view of the cooking device, and FIG. 13(b) isthe plan view of the cam, both representing a state where the latchmodule operates and the latch is moved to the secure lock position.

FIG. 14 is a graph showing a range of the cam in contact with a contactsurface of the latch, a contact position of the cam in contact with thecontact surface of the latch, a movement of the contact position of thecam in contact with the contact surface of the latch, and a position inwhich the cam presses a switch together, in addition to FIG. 8.

FIG. 15 shows a first case in which the cam is in a fourth mode.

FIG. 16 shows a second case in which the cam is in the fourth mode.

FIG. 17 shows a third case in which the cam is in the fourth mode.

FIG. 18 is a schematic view of an algorithm for searching and setting aninitial position of the cam.

FIG. 19 shows a control system including a controller.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present disclosure will describe in detail embodimentsof the invention with reference to the accompanying drawings.

The present disclosure may be implemented in many different manners andis not limited to the embodiments set forth herein. Certain features ofthe embodiments may be omitted and features of one embodiment may becombined with features of another embodiment. The embodiments areprovided so that this disclosure will be thorough and complete, and willenable those skilled in the art to make and use of the invention.

Hereinafter, according to an embodiment, an overall structure of acooking device to which a method of automatically opening a door isapplied will be described. However, it should be noted that theembodiments are not limited to a cooking device. The embodiments may beapplied to all appliances having a pull-down door. An appliance may bethat used in a home or commercially.

Referring to FIG. 1, according to an embodiment of the invention, anoven as a cooking device will be described as an example of anappliance. According to the present disclosure, the appliance is notlimited to a cooking device and a cooking device is not limited to anoven.

The cooking device includes a main body 10 having a substantiallyrectangular parallelepiped shape, an open front, and a cavity, and adoor 20 installed at a front of the main body 10 that can cover thecavity.

The main body 10 includes an outer housing (not shown in FIG. 1 to showan inner structure of the main body) that defines an outer appearance ofthe cooking device and an inner housing 11 installed in the outerhousing. The inner housing may be provided with the cavity openedforward. The cavity forms a cooking chamber. In an upper portion, alower portion, a rear portion, and side portion of the main body 10,various components needed for operation of the cooking appliance may beprovided.

The door 20 has a pull-down opening and closing structure about ahorizontal hinge shaft 314 disposed at a lower end of the door. In otherwords, the door 20 is rotated forward and downward with respect to themain body to be opened and is rotated rearward and upward with respectto the main body to be closed.

As shown in FIG. 1, the door 20 may open or close the front of thecooking chamber, and may cover not only the cooking chamber but also afront of an upper space of the cooking chamber. A display and a touchpanel, and the like may be installed on a front surface of the door 20with respect to the upper space of the cooking chamber. As shown in FIG.19, the display 90 and the touch panel 100 are connected to thecontroller 80. The controller 80 may be installed on an upper space ofthe cooking chamber or in the door 20 corresponding to the upper spaceof the cooking chamber.

A latch module 4 is provided at an upper side of the main body 10. Thelatch module 4 maintains a state where the door 20 is closed, or allowsfor manually opening or closing of the door 20, or automatically opensthe door 20, or securely locks the door 20 so that the door cannot to bemanually opened. A pin 22 that is engaged with or released from a hook51 of a latch 50 of the latch module 4 and an accommodation 21 that hasthe pin 22 are provided on a rear surface of the door 20 (see, forexample, FIG. 9(a)). The accommodation 21 provides a space capable ofaccommodating the hook 51.

The latch module 4 may be installed on the main body 10 and a distal endof the latch 50 of the latch module 4, i.e., the hook 51 may protrudeforward from the front surface of the main body 10.

The latch module 4 may be installed at one side on the door or on bothsides of the door, and the pin 22 and the accommodation 21 of the doormay be provided corresponding to the latch module.

FIGS. 2 and 3 illustrate a hinge module 300 that connects a door and amain body of a cooking device according to an embodiment of theinvention. The hinge module 300 includes a spring 323, a damper 350, anda sub-spring 370, and is connected to a front lower portion of the mainbody and a lower portion of the door. The spring 323 applies a force ofmoving the door in a direction of rotating a door 20 rearward andupward, i.e., the direction of closing the door. Accordingly, the spring323 opposes a force opening the door while the door is being opened anddescending.

Further, while the door is being opened, the damper 350 damps arotational force of the door to cause the door to be opened slowly. Asnecessary, the damper 350 may only provide a damping force while thedoor is being opened, or may provide the damping force while the door isbeing opened and while the door is being closed. The damping force maybe provided in all rotation angles in which the door is opened and/orclosed, or the damping force may be provided in a range among therotation angles.

The damper 350 may damp a force of opening the door at a predeterminedopening angle section of the door and may not provide the damping forcein a section beyond the opening angle section in which the damping forceis provided. FIG. 1 shows a structure in which the damper is damping inan opening angle section of an opening door corresponding to a2 to a3. Adamping beginning in angle a2 in which the damping starts when the dooris being opened may be 35±5°.

The sub-spring 370 applies a force in a direction of opening the door20. An opening angle range in which the sub-spring 370 applies the forcein the direction of opening the door may be 0° to a1.

Hereinafter, an operation of automatically opening a door will bedescribed with reference to FIGS. 1 to 3. In this embodiment, when auser touches a touch panel and the like to input a command of openingthe door, a latch module 4, which will be described later, releases anengaged state of the closed door. The door is opened by an elastic forceof the sub-spring 370 of the hinge module 300 to an initial openingangle a1. The predetermined angle a1 may be set to such an extent thatthe door may be subsequently further opened by the weight of the dooritself. The angle a1 may be, for example, about 10°.

The hinge module 300 connecting the main body 10 and the door 20includes a door bar 340 fixed to the door 20 and a housing 310 fixed tothe main body 10 that rotate about an opening and closing rotationalshaft 314. In another embodiment, the bar may be fixed to the main bodyand the housing may be fixed to the door.

In the housing 310, an inner link housing 330 is provided which ismovable along a longitudinal direction of the housing. A distal end ofthe inner link housing 330 is connected to the door bar 340 by a doorbar connecting hinge 331. As the door bar connecting hinge 331 isdisposed eccentric from the opening and closing rotational shaft 314 bya distance of r, when the door 20 (the door bar 340) opens, the door barconnecting hinge 331 rotates about the opening and closing rotationalshaft 314 and moves forward. Accordingly, the inner link housing 330also moves forward in the housing 310.

As the door 20 or the door bar 340 is opened from a closed state(vertical state) to an opened state (horizontal state) while beingrotated forward of the main body, a maximum opening angle a3 is 90°.Accordingly, the connecting hinge 331 also rotates by 90° about theopening and closing rotational shaft 314. The inner link housing 330also moves forward by a horizontal distance d3 in which the opening andclosing rotational shaft 314 rotates by 90°.

An insert pin 361 is installed in front of the inner link housing 330. Aslot pin 362 provided in front of the insert pin 361 and is fitted intoa guide slot 333 formed longitudinally at both sides of the inner linkhousing 330. Accordingly, the insert pin 361 is slidably installedforwardly and rearwardly in the inner link housing 330 within a rangeallowed by the guide slot 333. The insert pin 361 is inserted into thesub-spring 370. A front portion of the sub-spring 370 is supported bythe slot pin 362 and the rear portion thereof is supported by the innerlink housing 330. Accordingly, the sub-spring 370 applies the force ofmoving the slot pin 362 forward through the guide slot 333.

A contact surface 363 of the slot pin 362 pushes an inclined surfaceprovided at a lower rear end of the door bar 340 forward. As shown inFIGS. 2 and 3, as a height at which the slot pin 362 pushes the inclinedsurface forward is higher than a position of the opening and closingrotational shaft 314, at the beginning of opening the door, in the statewhere the door bar 340 stands vertically (closed state), the sub-spring370 applies the force of moving the door bar 340 in a direction ofrotating the door bar 340 forward and downward. Accordingly, at thebeginning of opening the door, the sub-spring 370 opens the door by theinitial opening angle a1. After the slot pin 362 moves to the foremostposition of the guide slot 333, the slot pin 362 does not move furtherand the sub-spring 370 does not apply force on the door bar 340.

Of course, in the section corresponding to the state where the door isclosed to the state where the opening angle of the door is the initialopening angle a1, a pressing force of the spring 323 in the direction ofclosing the door is less than a pressing force of the sub-spring 370 inthe direction of opening the door. Thus, in this section, the net forceis a force applied to the door in the opening direction thereof.

Note that in a closed state of the door, a force which is transferredfrom the pin 22 to the hook 51 of the latch 50 to move the latch in asecond direction w2 (see FIG. 6) by an opening force of the sub-spring370 is weaker than a force which is applied to the latch 50 to move thelatch in a first direction w1 by a spring in the latch module 4 (forexample, see FIG. 4), when the latch 50 is in a manual lock state, andthus the door maintains the closed state in spite of the force of thesub-spring 370 of a hinge module 300 to open the door.

After the door reaches the initial opening angle a1 from the closedstate, the door starts to open by the weight of the door itself. As thedoor bar 340 rotates about the housing 310 to further open the door, adamping force along with an opposing force against the door being openedare exerted on the door bar 340 by a damper 350 and a spring 323 to bedescribed later.

A second insert pin 320 inserted inside of the spring 323 is installedat a rear of the inner link housing 330. The second insert pin 320 isconnected to the rear of the inner link housing 330 through a joint pin322 at the inner housing. Both ends of the joint pin 322 at the innerhousing are fitted to a guide slot 315 provided at the housing 310. Theguide slot 315 for the joint pin 322 has an elongated shape extendingalong the longitudinal direction of the housing 310.

The second insert pin 320 is inserted into the compressed coil spring323 having greater elasticity in a compressed state. The second insertpin 320 may slidably move along the longitudinal direction of thehousing 310 through a spring-engaged plate 311 fixed to the housing 310.However; the distal end of the compressed coil spring 323 is engagedwith the spring-engaged plate 311 of the housing 310 and a supportingpin 312 that supports the spring-engaged plate 311 may be installed inthe housing 310 so as to maintain the force of the compressed coilspring 323.

A spring supporting pin 321 that fixes a rear end of the spring 323 isinstalled at a rear end of the second insert pin 320. The springsupporting pin 321 does not interfere with the housing 310.

Accordingly, when the door bar 340 opens from the main body 20, thejoint pin 322 of the inner link housing 330 is guided by the guide slot315 of the housing 310, and the inner link housing 330 and the secondinsert pin 320 are moved forward. Accordingly, the spring 323 starts tocompress between the spring-engaged plate 311 and the spring supportingpin 321, and the elastic force is gradually increased. The compressionlength d3 of the spring 323 corresponds to the horizontal movementdistance d3 of the inner link housing 330 in which the opening andclosing rotational shaft 314 rotates by 90°. When the opening angle ofthe door is less, the elastic force of the spring 323 is less. However,as the opening angle of the door is increased, the elastic force of thespring 323 is increased. The elastic force is applied in a direction ofopposing the door being opened.

A force in which the spring 323 pushes the door in the closing directionthereof when the door is opening is gradually increased from the openingangle a1 to the opening angle a3 of the door. As the force of the spring323 at the opening angle a1 of the door is less than the force (theopening force) in which the door is opened by the weight of the dooritself at the opening angle a1, the door pushed to the opening angle a1by the sub-spring 370 starts to open by itself.

The damper 350 is installed in the inner link housing 330. A piston 351of the damper 350 is supported by a damper pushing surface 332integrally fixed to the inner link housing 330. The piston 531 isinserted into a cylinder 352. A slot 353, in which a damper supportingpin 313 fixed to the housing 310 is fitted into is provided at thecylinder 352. That is, the cylinder 352 may move forward or backward bythe length of the slot 353. FIG. 3 shows a position between the slot 353of the damper 350 and the damper supporting pin 313 of the housing 310while the door is closed.

As the door opens and is rotated by a predetermined angle a2, the innerlink housing 330 moves forward in the horizontal direction by distanced2. Accordingly, the damper 350 is moved forward by the damper pushingsurface 332 of the inner link housing 330 and moves together. As thedamper is pushed forward, the damper pushing surface 332 pushes thepiston 351 forward; however, the slot 353 of the cylinder 352 has notengaged with the damper supporting pin 313. Thus, the piston 351 and thecylinder 352 move forward together with the inner link housing 330, anddoes not generate any damping force.

As soon as the opening angle of the door exceeds a2, the slot 353 of thedamper 350, which has been moving forward, is engaged with the dampersupporting pin 313, so that the cylinder 352 stops moving and the piston351 engages with the cylinder 352 such that the damper 350 starts tocompress. The damping force generated when the damper 350 compressesenables opening the door at a controlled speed in the sectioncorresponding to the opening angle a2 to a3.

For reference, a maximum damping distance (Lmax) of the damper 350itself, that is, a maximum stroke capable of generating the dampingforce by compressing in the damper, is set to be equal to or greaterthan the distance d3−d2 in which the inner link housing 330 moves whilethe damping force is applied to the door.

When the closed door is opening to opening angle a2, the door barconnecting hinge 331 also rotates by angle a2, so that the inner linkhousing 330 and the second insert pin 320 move forward by distance d2.While the inner link housing 330 and the second insert pin 320 insertedinside of the spring 323 move by the distance d2, the slot 353 of thedamper 350 moves without interference from the damper supporting pin 313of the housing 330, and thus the piston 351 and the cylinder 352 of thedamper do not engage. That is, in the section corresponding to theopening angle of 0 to a2 of the door, the elastic force of the spring323 is applied in a direction opposite to the opening force of the doorto control the opening speed of the door, but the damping force is notapplied.

When the closed door is opening to opening angle a3, the door barconnecting hinge 331 also rotates by angle a3, so that the inner linkhousing 330 and the second insert pin 320 move forward by distance d3.That is, the spring 323 is compressed by distance d3. That is, theelastic force of the spring 323 is applied in a direction opposite tothe opening force of the door in the section from 0° to a3 of theopening angle, and an opening speed of the door is controlled by theelastic force.

The maximum opening angle a3 may be regulated by the guide slot 315 ofthe housing 310 by regulating a slidable movement distance of the jointpin 322 of the inner link housing 330 within the guide slot 315.

The angle range in which the damper 350 damps the opening force of thedoor may start when the door is rotated about 30° to 40°, for example,and may be continued until the door is rotated by 90°. To summarize, thedoor is opened in a closed state by the sub-spring 370 to the initialopening angle a1, and then opened by its own weight while being opposedby the elastic force of the spring 323. When the door is rotated byopening angle a2 (about 30° to 40°), the damping force of the damper 350is applied to the door so that the opening speed of the door is sloweddown. The manner of opening the door as described above makes the userfeel comfortable.

Note that if the damping starts too early as the door is opening, timefor waiting for the door to be completely opened may take too long,resulting in an inconvenience to the user. On the other hand, if thedamping of the door starts too late, the door may be opening too quicklyto an extent that the opening speed of the door is too fast, and therebythe user may be surprised or feel uncomfortable, or the user may getinjured by the quickly opening door.

Thus, according to the embodiment, the damping beginning angle a2 atwhich the damper 350 starts to damp the opening force of the door is35±5°.

The damping force may be continuously applied up to 90° at which thedoor is completely opened or up to 85° which is about 5° less. It isalso conceivable that the damping force is not applied for an openingangle greater than 85° to prevent the door from being opened less than1° to 2° of the 90° required to completely open the door.

As described above, the damping beginning angle a2 is set to be greaterthan the forcedly opened angle a1. A section between the forcedly openedangle a1 and the damping beginning angle a2, for example, a range of 10°or more and 30° to 40° or less is configured so that the door is openedby the weight of the door itself without being damped by any damper 350.Of course, even in this section, the above-described elastic force ofthe spring 323 is applied in a direction that opposes the opening of thedoor, so that the opening of the door is sufficiently prevented fromopening too quickly in the section in which the door is opening by theweight of the door itself.

When such a structure of automatically opening the door is applied, itis possible to reduce user anxiety, and increase a quality of the doorbeing opened automatically, and there may be no need to install a handleprotruding forward from the door, thereby providing excellent appearanceto the user in the built-in installation.

Hereinafter, according to an embodiment, a latch module 4 capable ofautomatically opening a door or completely locking a door of a cookingdevice will be described with reference to FIGS. 4 to 13(b).

According to the embodiment, the latch module 4 includes a bracket 40 asan overall base. The bracket 40 may be made of sheet metal. An edge of arectangular metal plate is bent downward or upward. Accordingly, astructure in which the latch module 4 may be fixed to another body and astructure in which various parts, such as a drive 60, an elastic body90, and the like may be installed in the bracket 40 are provided.

The bracket 40 includes a cam accommodating hole 42 that provides aspace that accommodates a cam 70 which is a power transmitting portionand an through-hole 41 capable of regulating a section in which a latch50 pivotally installed in the bracket 40 pivots.

The latch 50 is pivotally installed on the bracket 40. The latch 50 hasa structure having a bent long metal plate, and a rear end of the latch50 is provided with a pivot shaft 54 as a center of pivot of the latch50 about the bracket 40. As the pivot shaft 54 is installed in a pivothole (not shown), the latch 50 is pivotally installed on the bracket 40.

A rear portion of the latch 50 including the pivot shaft 54 is arrangedover the bracket 40. On one side of the latch 50 arranged over thebracket 40, a contact surface 55 is provided to be in contact with alatch position adjusting profile 73 of the cam 70 and an extension 58 isprovided that interacts with the cam 70 to mechanically complement anoperation error of the latch 50. The extension 58 extends verticallyfrom the contact surface 55 and a substantially ‘L’-shape is formedbetween the contact surface 55 and the extension 58.

An insertion portion 56 is formed at an intermediate portion of thelatch 50 that is bent downward and forward so as to decline from a frontend of the rear portion and is inserted through the through-hole 41 ofthe bracket 40. The through-hole 41 has an arc shape and has a size thataccommodates a locus of the swivel of the latch 50 when the insertionportion 56 is inserted into the through-hole 41.

An arc-shaped sliding bead surface 43 that supports the pivoting of thelatch 50 is provided at a position closer to the pivot shaft 54 than thethrough-hole 41 at the bracket 40. The sliding bead surface 43 protrudesfrom the surface of the bracket 40 to contact a bottom surface of thelatch 50, thereby preventing friction from occurring via a directcontact of a top surface of the bracket 40 and the bottom surface of thelatch 50.

A front end of the insertion portion 56 is bent forward again to extendforward in the horizontal direction, i.e., parallel with the rearportion. A hook 51 is provided at a distal end of the latch 50. The hook51 engages with or releases from a pin 22 of the door.

The latch 50 includes a hole 57 capable of engaging with an end of aspring 90 that acts as an elastic force. The spring 90 has one end fixedto the hole 57 and an other end fixed to the bracket 40. Accordingly,the spring 90 pulls the latch 50 towards the spring. The spring 90 isarranged to be adjacent to a first direction w1 of the pivotingdirection of the latch 50 and applies a force so as to pivot the latch50 in the first direction w1.

The cam 70 is rotatably installed to be adjacent to the first directionw1 of the latch 50. A hole 711 as the center of rotation of the cam 70is disposed vertically on the cam so that the cam 70 has a verticalrotational axis. The cam 70 is installed into the cam accommodating hole42 of the bracket 40 so that an upper portion of the cam 70 is exposedover the bracket 40 and a lower portion of the cam 70 is exposed belowthe bracket 40.

The cam 70 includes the latch position adjusting profile 73 thatcontacts the contact surface 55 of the latch 50 described above andadjusts the position of the latch 50 based on a rotational position ofthe latch position adjusting profile 73, and a switch pressing profile72 that presses the switches 81 and 82 to be described later orpress-releases the switches 81 and 82.

The latch position adjusting profile 73 is provided at the upper portionof the cam, and the switch pressing profile 72 is provided at the lowerportion of the cam. The latch position adjusting profile 73 is exposedabove the bracket 40 and contacts the contact surface 55 of the latch 50when the cam 70 is installed on the bracket 40. The switch pressingprofile 72 is exposed below the bracket 40 and presses or press-releasesthe switches 81 and 82 to be described later provided at the lowerportion of the bracket 40.

For reference, a material of the cam 70 may be a synthetic resin havinggood strength and heat resistance, such as poly phenylene sulfide (PPS),and thereby abrasion generated when the cam rotates is minimized andstability in an environment of the home appliance having hightemperature may be provided.

The cam 70 is rotationally driven by a motor 60 as a driver. Accordingto the embodiment, the cam 70 may be directly connected to therotational shaft 61 of the motor 60. The motor 60 may be abi-directional rotational motor capable of both clockwise rotation andcounter-clockwise rotation. The motor 60 is fixed to the upper portionof the bracket 40 such that the rotational shaft 61 extends downward andthe rotational shaft 61 is inserted into the axis hole 711 of the cam70.

The first switch 81 and the second switch 82 are installed at the bottomsurface of the bracket 40. The first switch 81 and the second switch 82may be a micro switch having buttons 811 and 812, respectively. Thebuttons 811 and 812 of the switches provided on the bracket protrude tosubstantially face a center of the cam. The buttons 811 and 812 arearranged with an angle b of 90° or more and less than 180° with respectto the center of rotation 711 of the cam and may be arranged at the samedistance from the center of rotation of the cam. Preferably, the angle bmay be in the range of 110° to 160°, and more preferably in the range of120°.

Referring to FIG. 6, a latch according to an embodiment will bedescribed. The hook 51 is provided at the distal end of the latch 50,that is, a front end thereof, is opened laterally, specifically, in afirst direction w1 in which the latch 50 pivots. Inward of the hook 51,an engaging surface 52 that engages with the pin 22 of the door isprovided. The engaging surface 52 includes a disengaging inclinedsurface 521 and a secure lock surface 522. The disengaging inclinedsurface 521 is arranged closer to the first direction w1 on the engagingsurface 52 and the secure lock surface 522 is arranged closer to asecond direction w1 in which the latch 50 pivots in the engaging surface52. That is, the disengaging inclined surface 521 is arranged closer tothe opening end of the hook 51 than the secure lock surface 522 which isarranged deeper into the hook 51.

The disengaging inclined surface 521 has a surface inclined with respectto a horizontal axis in an opening direction of the door toward thefirst direction w1. When the latch 50 pivots about a pivot shaft 54 inthe first direction w1, the pin 22 of the door contacts the disengaginginclined surface 521 and the latch 50 is disposed in the manual lockposition.

The secure lock surface 522 has a surface inclined with respect to thehorizontal axis in the closing direction of the door toward the seconddirection w2. When the latch 50 pivots further in the first directionw1, the pin 22 contacts the secure lock surface 522 and the latch 50 isdisposed in a secure lock position.

The disengaging inclined surface 521 and the secure lock surface 522 areconnected with a smooth curved surface. Thus, as the latch 50 pivots,when the pin 22 of the door in contact with the disengaging inclinedsurface 521 slides adjacent to the secure lock surface 522, the slidingmay be smoothly made over to the secure lock surface 522. In particular,as the movement of the latch 50 is made by an elastic force of thespring 90, the movement of the latch 50 may be more reliably made if thesliding between the disengaging inclined surface 521 and the secure locksurface 522 is made smooth.

An inclined insertion surface 53 is provided on an outer surface of thehook 51 opposite to the disengaging inclined surface 521. The inclinedinsertion surface 53 is inclined with respect to the horizontal axis inthe closing direction of the door toward the second direction w2 whenthe latch 50 is in the manual lock position. The inclined insertionsurface 53 contacts the surface of the pin 22 of the door when the latchis in the manual lock position. That is, the hook 51 has a shape thatgradually becomes thinner, that is, sharper, toward the end by thedisengaging inclined surface 521 and the inclined insertion surface 53.The inclined insertion surface 53 may extend to the outer surface of thehook 51 that is opposite to the secure lock surface 522.

The contact surface 55 of the latch 50 in contact with the cam 70 isprovided at the side of the latch 50. The contact surface 55 is arrangedin adjacent to a second direction w2 about the center of rotation of thecam. An extension 58 extending outward from the contact surface 55 isfurther provided at one end of the contact surface 55. The extension 58and the contact surface 55 have a substantially 1′-shape and the contactsurface 55 and the extension 58 are arranged to surround the cam 70.

An sub-contact surface 59 is provided laterally with respect to anextending direction of the extension 58, which faces the cam, and insome cases contacts and interacts with the surface of the cam. Thesub-contact surface 59 protrudes from the extension 58 so that otherthan the sub-contact surface 59, other portions of the extension 58 doesnot interact with the cam 70.

The sub-contact surface 59 approaches the cam 70 when the latch 50pivots in the second direction w2. The sub-contact surface 59 moves in adirection away from the cam as the latch 50 pivots in the firstdirection w1.

The extension 58 is not necessarily integrally formed with a body of thelatch 50, but may be manufactured as a separate component and thenassembled. The extension 58 does not have to behave like a rigid bodywith the body of the latch 50. It is enough for the extension 58 totransmit such a force to the body of the latch 50 that the cam 70 movesthe extension 58 in the first direction w1 and the latch 50 moves from afirst basic position (see FIG. 9(b)) to a third basic position (see FIG.13(b)) or the latch is in the third basic position.

When the force is applied to the contact surface 55 of the latch 50 bythe cam 70 in the second direction w2, that is, the latch 50 is pivotedfrom the first basic position to the second basic position (see FIG.10(b)) by the cam 70, the extension 58 does not interact with the cam70.

A feature of the sub-contact surface 59 will now be described. The cammay include an oblong shape. When the cam 70 rotates and the radius ofthe cam 70 in contact with the contact surface 55 of the latch 50 isreduced, the latch 50 pivots in the first direction w1, and the radiusof the cam 70 that faces the sub-contact surface 59 of the latch 50increases. When the latch 50 does not pivot in the first direction w1although the radius of the cam 70 contacting the contact surface 55 ofthe latch is reduced so that the latch 50 can pivot in the firstdirection w1, the radius of the cam 70 that faces the sub-contactsurface 59 increases sufficiently as to interact with the sub-contactsurface 59, and the sub-contact surface 59 is pushed in a direction awayfrom the cam 70 so that the latch 50 may be forcedly pivoted in thefirst direction w1.

A distance dmp between the center of rotation of the cam 70 and thesub-contact surface 59 when the latch 50 is in the first basic position(see FIG. 9(b)) and a distance dop between a center of rotation of thecam 70 and the sub-contact surface 59 when the latch 50 is in the secondbasic position (see FIG. 10(b)), and a distance dlp between the centerof rotation of the cam and the sub-contact surface when the latch is inthe third basic position (see FIG. 13(b)) has a relationship ofdop<dmp<dlp.

Referring to FIGS. 5, 7, and 8, a cam according to an embodiment will bedescribed. A latch position adjusting profile 73 of the cam 70 includesthree surfaces having different radiuses from one another, that is, acontact surface for manual lock 731, a contact surface for automaticopening 732 and a contact surface for secure lock 733. The threesurfaces have different radiuses from one another and are connected toeach other by a connecting surface 734 that has a gradually increasingor reducing radius, respectively.

The contact surface for manual lock 731 includes a first radius. Thefirst radius may be configured such that the latch 50 is disposed at aposition where the door may be manually opened and closed in a state inwhich the first radius contacts the latch 50. In this state, the pin 22of the door contacts the disengaging inclined surface 521 or theinclined insertion surface 53 of the hook 51. Accordingly, the spring 90pulls the latch 50 in the first direction w1 and the contact surface formanual lock 731 of the cam 70 contacts the latch 50 (see FIG. 9(a), 9(b)or 12(a), 12(b)). In this state, when the user pulls the door in theopening direction thereof, the door may be opened. When the user closesthe door, the door may be closed.

The contact surface for automatic opening 732 includes a second radius.The second radius is configured so that the latch 50 may be rotated inthe second direction w2 to the position in which the latch 50 isreleased from the pin 22 of the door in a state in which the secondradius contacts the latch 50. The second radius has a radius greaterthan the first radius. That is, when the spring 90 pulls the latch 50 inthe first direction w1 and the contact surface for automatic opening 732of the cam contacts the latch 50 (see FIG. 10(a), 10(b) or 11(a),11(b)), the latch 50 is released from the pin 22 of the door.

The contact surface for secure lock 733 includes a third radius. Thethird radius is configured such that the latch 50 completely securelylocks the door while being in contact with the latch 50 so that the doorcannot be opened even when the door is pulled to open by the user. Inthis state, the pin 22 of the door contacts the secure lock surface 522of the hook 51. Thus, when the spring 90 pulls the latch 50 in the firstdirection w1 and the contact surface for secure lock 733 of the cam 70contacts the latch 50 (see FIGS. 13(a), 13(b)), even if the user pullsthe door in the opening direction, the door may not open. That is, thestate may be referred to as a completely locked state, for example, forself-cleaning.

A diameter rM1 of a cam surface in contact with the sub-contact surface59 when the cam is in the first mode and the first radius of the camcontacts the contact surface of the latch (see FIG. 9(b)), a diameterrM2 of a cam surface that faces the sub-contact surface 59 when the camis in the second mode and the second radius of the cam contacts thecontact surface of the latch (see FIG. 10(b)), and a diameter rM3 of acam surface that faces the sub-contact surface 59 when the cam is in thethird mode and the third radius of the cam contacts the contact surfaceof the latch (see FIG. 13(b)) have a relation of rM2≤rM1≤rM3.

When the cam is in the first mode state, and the first radius 731contacts the contact surface 55 of the latch 50, a portion of the camsurface that faces the sub-contact surface 59 may be the first radius731, the third radius 733 or a connecting surface 734 connecting thefirst radius 731 and the third radius 733. According to the presentdisclosure, FIGS. 9(b) and 12(b) show that the cam surface that facesthe sub-contact surface 59 is the first radius 731.

When the cam is in the second mode, and the second radius 732 is in aposition in contact with the contact surface 55 of the latch 50, the camsurface that faces the sub-contact surface 59 may be the first radius731 (see FIGS. 10(b) and 1(b)).

When the cam is in the third mode, and the third radius 733 is in theposition in contact with the contact surface 55 of the latch 50, the camsurface in contact with the sub-contact surface 59 may be the secondradius 732 (see FIG. 13(b)).

As shown in FIG. 9(b), when the cam 70 is in the first mode state, andthe first radius 731 contacts the contact surface 55 of the latch 50,the radius rM1 of the cam surface that faces the sub-contact surface 59is less than a distance dmp between a position mp of the sub-contactsurface 59 and the center of rotation 711 of the cam 70 when the latch50 is in the first basic position, and is equal to or less than thedistance dop between the position op of the sub-contact surface 59 andthe center of rotation 711 of the cam 70 when the latch 50 is in thesecond basic position (see FIG. 10(b)). That is, the relation ofrM1≤dop<dmp is satisfied.

As shown in FIG. 10(b), when the cam 70 is in the second mode state, andthe second radius 732 contacts the contact surface 55 of the latch 50,the radius rM2 of the cam surface that faces the sub-contact surface 59is equal to or less than the distance dop between the position op of thesub-contact surface 59 and the center of rotation 711 of the cam 70 whenthe latch 50 is in the second basic position. That is, rM2≤dop.

As shown in FIGS. 9(b) and 10(b), the relation of rM1≤rM2≤dop<dmp may beexpressed based on the conditions.

As shown in FIG. 13(b), when the cam is in the third mode state, and thethird radius 733 of the cam 70 contacts the contact surface 55 of thelatch 50, a radius rM3 of the cam surface that faces the sub-contactsurface 59 is greater than a distance dmp between the position mp of thesub-contact surface 59 and the center or rotation 711 of the cam 70 withthe latch 50 being in the first basic position and is equal to or lessthan a distance dlp between a position 1 p of the sub-contact surface 59and the center of rotation 711 of the cam 70 with the latch 50 is in thethird basic position. That is, the relation of dmp<rM3≤dlp is satisfied.

All of the above conditions are expressed as follows:

rM1≤rM2≤dop<dmp<rM3≤dlp.

On the other hand, a switch pressing profile 72 of the cam 70 has twopressing bosses having substantially the same radius. A first pressingboss 721 and a second pressing boss 722 are not arranged in a straightline, that is 180° opposite from each other, but are disposed at anobtuse angle. The angle of the two pressing bosses may correspond to anangle between the buttons 811 and 812 of the first switch and the secondswitch, and the radius of the two pressing bosses may be configured suchthat the pressing boss presses or press-releases the button as the camrotates.

The first pressing boss may press the first switch or the second switchor not press the two switches depending on the rotational position ofthe cam. The second pressing boss may press the first switch or thesecond switch or not press both switches depending on the rotationaldirection of the cam.

Since the angle of the two pressing bosses corresponds to the angle ofthe buttons of the two switches, the state where the first pressing bosspresses the first switch and the second pressing boss presses the secondswitch, that is, a first mode state where the two pressing bosses pressthe two switches, a second mode state where the second pressing bosspresses the first switch and the first pressing boss does not press aswitch, a third mode state where the first pressing boss presses thesecond switch and the second pressing boss does not press a switch, anda fourth mode state where the two pressing bosses do not press anyswitches may be implemented.

Each mode of the switch pressing profile 72 and the latch positionadjusting profile 73 may be related to each other. That is, in the firstmode, the contact surface for manual lock 731 may contact the latch todispose the latch in the manual lock state. In the second mode, thecontact surface for automatic opening 732 may contact the latch so thatthe latch is in the open position. In the third mode, the contactsurface for secure lock 733 may contact the latch so that the latch isdisposed in the secure lock position.

Hereinafter, an operation of a latch module according to an embodimentwill be described with reference to FIGS. 9 to 13(b).

<Manual Lock State>

FIGS. 9(a) and 9(b) illustrate a manual lock state. A latch module isprovided. That is, when the two pressing bosses 721 and 722 press thebuttons 811 and 812 of the two switches, respectively, a contact surfacefor manual lock 731 which is a first radius of the latch positionadjusting profile 73 contacts a contact surface 55 of a latch 50. Thespring 90 pulls the latch 50 in the first direction w1 (a direction inwhich the hook 51 pivots leftward in FIG. 9(a)).

When the user pulls the door 20 in such a manual lock state, a rearsurface of the pin 22 presses on the disengaging inclined surface 521 ofthe hook 51. The disengaging inclined surface 521 is inclined outwardtoward the first direction w1 so that the force is applied to the hook50 in the second direction w2 by a force in which the pin 22 presses onthe disengaging inclined surface 521, and accordingly, the latch 50pivots in the second direction w2 with a force greater than the elasticforce of the spring 90 (i.e., as the latch 50 pivots in the seconddirection w2, the contact surface 55 of the latch moves away from thecontact surface for manual lock 731). As a result, the hook 51 that isengaged with the pin 22 is released so that the door is opened.

As described above, as the relation of rM1≤dop<dmp is satisfied, theextension 58 does not interact with the cam during the pivot of thelatch 50 in the second direction w2 for the manual opening of the doorand the latch 50 may freely rotate in the second direction w2.

When the door is opened and the pin 22 is released from the hook 51, asa force in which the pin 22 pushes the hook 51 in the second directiondisappears, the latch 50 pivots in the first direction w1 by means ofthe spring 90 until the contact surface 55 of the latch 50 contacts thecontact surface for manual lock 731, so that the latch is returned to amanual lock position as shown in FIGS. 12(a) and 12(b).

In this state, when the user closes the door as shown in FIG. 12(a), thesurface of the pin 22 pushes the inclined insertion surface 53 of thehook 51. As the inclined insertion surface 53 has a form inclined to aclosing direction of the door toward the first direction w1, a force ofpivoting in the second direction w2 is applied to the hook 51 in whichthe surface of the pin 22 presses against the inclined insertion surface53 in the closing direction. Then, the latch 50 pivots in the seconddirection w2 with a force greater than the elastic force of the spring90. As the door is closed, the force on the hook 51 is released from alocus of the moving pin 22. As shown in FIG. 9(a), when the door isclosed, via the elastic force of the spring 90, the latch pivots againand returns in the first direction w2 by the elastic force of the springuntil the contact surface 55 of the latch 50 contacts the contactsurface for manual lock 731.

Similarly, as the relation of rM1≤dop<dmp is satisfied, during the pivotof the latch 50 in the second direction w2 for manual closing the door,the extension 58 is not interfered with the cam 70 and the latch 50 mayfreely move in the second direction w2.

As described above, according to the embodiment, with the latch module4, it is possible to open the door by manually pulling the door by theuser, or close the door by pushing the door toward the main body.

<Automatic Opening Operation>

An Automatic opening operation of the latch module according to anembodiment will now be described. As shown in FIG. 9(a), when the userinputs an automatic opening command of a door through an input device, abidirectional rotational motor 60 rotates in any one direction, that is,a first rotational direction by a controller 80, and the cam 70 isrotated in a first rotational direction c1. Then, a pressed state of thetwo switches is released, and the cam 70 continues to rotate. As shownin FIG. 10(a), the rotation of the cam 70 continues until a secondpressing boss 722 presses a first switch 81. When the second pressingboss 722 presses the first switch 81, the bidirectional rotational motor60 is stopped by the controller 80 that senses the pressed state, andthe rotation of the cam in the first rotational direction c1 is alsostopped. That is, the cam 70 is rotated in the first rotationaldirection c1 by an angle b of the two pressing bosses and stopped (seeFIG. 7).

As shown in FIG. 10(a), as the first pressing boss 721 and the secondpressing boss 722 are not on a straight line passing through a center ofrotation 711 of the cam 70 and have an obtuse angle, the second pressingboss 722 presses the first switch 81 while the first pressing boss 721does not press the second switch 82.

As the latch 50 is elastically supported by the spring in a direction incontact with the cam 70, the latch pivots while being in contact withthe latch position adjusting profile 73 of the cam 70 depending on theradius of the latch position adjusting profile 73 during the rotation ofthe cam 70. As the cam 70 is rotated by the angle b in the firstrotational direction c1, a position of the latch position adjustingprofile 73 contacting the contact surface 55 of a latch 50 is moved fromthe contact surface for manual lock 731 to the contact surface forautomatic opening 732 (as shown in FIG. 8, the position of the latchposition adjusting profile 73 contacting the contact surface 55 of thelatch 50 is moved from a vicinity of 250° (a contact surface for manuallock 731) to a vicinity of 20° (a contact surface for automatic opening732) in a direction of increasing angle). As shown in FIGS. 10(a) and10(b), as the radius of the cam 70 in contact with the latch 50 isincreased from the first radius to the second radius, the cam 70 pushesthe contact surface 55 of the latch 50 in a second direction w2 with aforce greater than an elastic force of the spring 90. Accordingly, thehook that is locked with the pin 22 of the door is released.

As described above, the relation of rM1≤rM2≤dop<dmp is satisfied.Further, while the cam 70 is moved from a first mode to a second mode, acondition in which the radiuses rM1 and rM2 of a cam surface that facesthe sub-contact surface 59 is less than distances dmp and dop betweenthe sub-contact surface 59 and the center of rotation of the cam iscontinuously satisfied. Therefore, when the cam is rotated in the firstrotational direction c1 for automatically opening the door and the latchis pivoted in the second direction w2, the cam 70 does not interact withthe extension 58 and the latch 50 may freely rotate in the seconddirection w2.

When the door is closed, that is, when an opening angle thereof is 0°,according to an embodiment, the sub-spring 370 of the hinge module 300applies the elastic force in the direction of opening the door.Therefore, as shown in FIG. 10(a), the door is moved in an openingdirection od when the hook 51 is no longer locked with the pin 22 as thelatch 50 is moved in the second direction w2 by the cam. As thesub-spring 370 of the hinge module 300 applies the elastic force in adirection of opening the door when the opening angle is 0°, an operationof opening the door instantly occurs when the lock of the hook 51 withrespect to the pin is released.

For reference, the door would be opened at the position at which sum ofthe force transmitted from the sub-spring 370 of the hinge module to thehook 51 to move the latch 50 in the second direction w2 and the force ofthe drive 60 is greater than the applied force of moving the latch 50 ina first direction w1 by the elastic force of the spring 90, as the forceof the drive 60 is transmitted to the latch 50 and the latch 50 moves inthe second direction w2.

Accordingly, when the door is opened by an initial opening angle a1, thedoor may automatically opened by its own weight.

As shown in FIG. 11(a), as the bi-directional rotational motor 60rotates in the other direction, that is, a second rotational directionc2, the cam rotates in a second rotational direction c2. Then, thepressing of the second pressing boss 722 with respect to the firstswitch 81 is released. As shown in FIG. 12(a), the rotation of the cam70 in the second rotational direction c2 continues until the twopressing bosses 721 and 722 push the two switches 81 and 82,respectively. That is, the cam 70 is rotated in the second rotationaldirection c2 by the angle b of the two pressing bosses and then stopped(see FIG. 7).

As described above, the automatic opening operation may be performedcontinuously. That is, as shown in FIG. 9(a), when the command ofautomatically opening the door is inputted, as the cam 70 is rotated inthe first rotational direction c1, the cam is moved to the positionshown in FIGS. 10(a) and 11(b) by the angle b. Accordingly, the secondpressing boss 722 presses the first switch 81, the cam 70 inverselyrotates again in the second rotational direction c2 so that the cam 70is returned to the state as shown in FIG. 9(a). As described above, thecommand of automatically opening the door enables rotating the cam 70 inthe first mode by the angle b1 in the first rotational direction c1 andmoving the cam 70 in the second mode, and immediately returning the camto the first mode again. That is, in accordance with the command ofautomatically opening the door, the cam operates in the order of thefirst mode→the rotation in the first rotational direction (the fourthmode)→the second mode→the rotation in the second rotational direction(the fourth mode)→the first mode.

A secure lock operation according to an embodiment will now bedescribed. As shown in FIG. 9(a) in a general state, when a user inputsa self-cleaning command through the input device, the controller 80determines whether the door is closed through a door sensor 88. If thedoor is closed, the controller 80 controls the bidirectional rotationalmotor 60 to rotate in a second rotational direction so that a cam 70rotates in a second rotational direction c2. The pressed state of thetwo switches are released and the cam 70 continues to rotate. As shownin FIG. 13(a), the rotation of the cam 70 continues until a firstpressing boss 721 presses a second switch 82. When the first pressingboss 721 presses the second switch 82, the bidirectional rotationalmotor 60 is stopped by the controller 80, and accordingly, the rotationof the cam in the second rotational direction c2 is stopped. That is,the cam 70 is stopped after being rotated in the second rotationaldirection c2 by the angle b of the two pressing bosses.

As the first pressing boss and the second pressing boss are not on astraight line passing through the center of rotation of the cam 70 andhave an obtuse angle, as shown in FIG. 13(a), the first pressing boss721 presses the second switch 82 while the second pressing boss 722 doesnot press the first switch 81.

As the latch 50 has elastic force in the direction in contact with thecam 70 by the spring 90, while the cam 70 rotates, the latch 50 pivotsdepending on the contact of radius of the latch position adjustingprofile 73 of the cam 70. As the cam rotates in the second rotationaldirection c2 by the angle b, the position of the latch positionadjusting profile 73 contacting the contact surface 55 of the latch 50is moved from the contact surface for manual lock 731 to the contactsurface for secure lock 733 (as shown in FIG. 8, the radius of the camis decreased from about 250° (contact surface for manual lock 731) to110° (contact surface for secured lock 733)). Accordingly, the radius ofthe cam 70 that contacts the latch 50 is reduced from the first radiusto the third radius, so that the spring 90 further pulls the latch 50 inthe first direction w1 into the hook 51 as shown in FIG. 13(a).Accordingly, as the pin 22 of the door moves deeply into the hook 51,the rear surface of the pin 22 contacts the secure lock surface 522 ofthe hook 51. As the pin 22 of the door moves from the disengaginginclined surface 521 to the secure lock surface 522, the disengaginginclined surface 521 and the secure lock surface 522 may be connectedvia a smooth curved surface. When the spring 90 pulls the latch 50, thepin may be naturally moved smoothly from the disengaging inclinedsurface 521 to the secure lock surface 522.

The movement of the latch 50 in the first direction w1 is made by theelasticity of the spring 90. Therefore, if the pin 22 of the door is notcompletely moved inside the hook 51 and is stuck in a transitoryposition in the hook, or if the pivoting of the latch becomes stiff oris stuck due to foreign substances and the like, even if the cam 70rotates in the second rotational direction c2 and moves from the firstmode to the third mode, the latch 50 may not pivot correspondingly toreach the third basic position from the first basic position.

However, as described above, the relation of dop<dmp<rM3≤dlp issatisfied. That is, a point at which the cam 70 contacts the contactsurface 55 of the latch 50 is moved from the first radius 731 to thethird radius 733 as the cam 70 rotates, the radius of the surface of thecam 70 that faces the sub-contact surface 59 may exceed the distance dmpbetween the position mp of the sub-contact surface 59 and the center ofrotation 711 of the cam 70 when the latch 50 is in the first basicposition.

Therefore, even if the latch is engaged in the first basic position orbetween the first basic position and the second basic position, which isfurther away from the first basic position, while the cam 70 is rotatedfrom the first mode to the third mode, the cam surface contacts thesub-contact surface 59 of the latch 50 and pushes the sub-contactsurface 59 in the direction away from the cam, causing a kinematicinterference such that the latch 50 is forcedly rotated in the firstdirection w1. Thus, the latch is surely moved to the third basicposition.

As shown in FIG. 13(a), as the secure lock surface 522 is inclined in aclosing direction toward the first direction w1, when the user pulls onthe door, the hook receives more force to pivot in the first directionw1. Therefore, even if the user pulls on the door, the door may not beopened.

In particular, if the relation of rM3=dlp is satisfied, the latch 50 maysurely reach the third basic position. When an external force is appliedto the latch 50 disposed in the third basic position and the latch ispivoted in the second direction w2, as the cam 70 already contacts thesub-contact surface 59 of the latch 50, the pivoting of the latch 50 inthe second direction w2 may be surely prevented via the kinematicinterference.

In this state, a self-cleaning operation may proceed. The cavity isheated to 400° C. and maintained for a few minutes. An inner temperatureof the cavity is measured by a temperature sensor 85. Even if theself-cleaning operation is completed, an internal temperature of thecavity is continuously monitored by the controller until the internaltemperature falls.

When the internal temperature is lowered to a safe level, the controller80 rotates the bidirectional rotational motor 60 in the first rotationaldirection c1 and rotates the cam 70 in the first rotational directionc1. Then, the pressing of the first pressing boss 721 with respect tothe second switch 82 is released. As shown in FIG. 9(a), the rotation ofthe cam 70 in the first rotational direction c1 continues until the twopressing bosses 721 and 722 press the two switches 81 and 82,respectively. That is, the cam 70 is rotated in the first rotationaldirection c1 by the angle b of the two pressing and then stopped.

From the position shown in FIG. 9(a), when the self-cleaning command isinputted, the cam 70 is rotated by the angle b in the second rotationaldirection c2 to the position shown in FIG. 13(a), and the first pressingboss 721 presses the second switch 82, the rotation of the bidirectionalrotational motor 60 and the cam 70 is stopped. Then, self-cleaningoperation proceeds. After the self-cleaning operation is completed, thecam 70 rotates in the first rotational direction c1 and return to thestate as shown in FIG. 9(a).

As described above, the self-cleaning command enables rotating the cam70 in the first mode by the angle b in the second rotational directionc2. After the self-cleaning operation, the cam returns to the first modeagain. That is, according to the self-cleaning command of the door, thecam is operated in the order of the first mode→the rotation in thesecond rotational direction (the fourth mode)→the third mode→therotation in the first rotational direction (fourth mode)→the first mode.

As described above, according to the embodiment, both the manual lockstate of the door, the automatic opening operation of the door, and thesecure lock operation of the door may be implemented by one latch, onedrive and one power transmitting portion.

Referring to FIG. 14, an initial position search control of latch modulewill be described. The latch is in three basic positions such as themanual lock position, the automatic opening position, and the securelock position, depending on whether the contact surface 55 of a latch 50contacts any of the radiuses 731, 732, 733 of the latch positionadjusting profile 73.

As described above, the rotational displacement of the cam 70 iscontrolled by the two switches 81 and 82 and the switch pressing profile72 of the cam 70. The controller 80 determines a rotational directionand a rotation or non-rotation of a bidirectional rotational motor basedon four modes of the two switches 81 and 82 (the first mode in which thetwo switches are pressed, the second mode in which the first switch isonly pressed, the third mode in which the second switch is only pressed,and the fourth mode in which the two switches are not pressed) tocontrol a rotational angle or a rotation or non-rotation of the cam.

As shown in FIG. 14, in a first mode M1 in which the switch pressingprofile 72 presses the two switches, the manual lock state (the state ofFIGS. 10(a) and 12(a)) in which the first radius 731 of the latchposition adjusting profile 73 contacts the latch 10.

In this state, when the cam 70 rotates in the first rotational directionC1, the position of the latch position adjusting profile 73 in contactwith the latch 50 is moved to the right side of the graph in FIG. 14. Inthis process, a first pressing boss 721 of the cam 70 is moved in anangle between the two switches shown in FIG. 15.

When the switch pressing profile 72 of the cam 70 is moved to a positioncorresponding to the second mode M2 in which the first switch is onlypressed and then stopped, it can be confirmed that the cam 70 and thelatch 50 are in the automatic opening state (the state of FIGS. 10(a)and 11(a), that is, the state in which the second radius 732 of thelatch position adjusting profile 73 of the cam 70 contacts the latch 50.The cam 70 that has reached the second mode rotates again in the secondrotational direction c2 and moves from the second mode M2 to the firstmode M1.

When the cam rotates in the second rotational direction C2 in the firstmode M1, the latch position adjusting profile 73 in contact with thelatch 50 is moved to the left of the graph in FIG. 14. In this process,the a second pressing boss 722 of the cam 70 is moved between the anglesof the two switches shown in FIG. 16.

When the switch pressing profile 72 of the cam 70 is moved to a positioncorresponding to a third mode M3 in which the second switch is onlypressed and then stopped, it can be confirmed that the cam 70 and thelatch 50 are in the secure lock state (the state of FIG. 13(a), that is,the state in which the third radius 733 of the latch position adjustingprofile 73 of the cam 70 contacts the latch 50. After the self-cleaningoperation, the cam 70 that has reached the third mode rotates again inthe first rotational direction c1 and moves from the third mode M3 tothe first mode M1.

As described above, the controller 80 determines the position of the cam70 and controls the rotation of the cam 70 based on the state where atleast one of the switches is pressed, that is, the first mode, thesecond mode and the third mode.

However, in situations such as where the cooking device is turned offdue to a power failure, and the like and the cooking device is turned onagain, the controller needs to determine whether the current position ofthe cam is in any one mode from the first mode to the fourth mode.

As a result of determination, if the cam is currently in any one mode ofthe first mode, the second mode and the third mode depending on thepressed state of the switch, the current position of the cam may beclearly determined. Therefore, it is possible to precisely control thestate of the latch module (the manual lock, the automatic opening, andthe secure lock) by controlling the drive and the cam.

However, as a result of the determination, if the cam is in the fourthmode state where none of the switches are pressed, it is not possible toclearly determine the current position of the cam. For example,referring to FIG. 14, all the remaining ranges except for the first modeM1, the second mode M2 and the third mode M3 shown are the fourth modeM4.

According to the embodiment, when a current state of the cam and thelatch cannot be determined in the initial operation of the cookingdevice, the position is initialized, which may be a position search andan initial position setting operations.

When the cam is in the fourth mode, with respect to searching theposition and setting the initial position, the initial position may besearched by rotating the cam in any one direction and determining aninitially pressed switch. For example, when the cam and the latch arepositioned where the cam in the fourth mode, the cam is rotated in anydirection to reach any one of the first mode M1, the second mode M2 andthe third mode M3.

However, according to the embodiment, as the latch module 4 isincorporated with an automatic opening function of the door, there is aproblem that the door may be automatically opened when the controller 80reaches the second mode M2 while searching for the initial position ofthe cam 70. That is, the cam should not reach the second mode M2 duringthe rotation of the cam while determining the initial position of thecam.

Thus, according to the embodiment, the switches 81 and 82 are arrangedso that the buttons 811 and 812 have a predetermined angle b so that thebuttons 811 and 812 are not arranged on a straight line on the center ofrotation of the cam, and the cam has a switch pressing profile 72 havingtwo pressing bosses 721 and 722 having an angle corresponding thereto,and the bidirectional rotational motor 60 is used as the drive 60.

The motor 60 is driven in the first rotational direction c1 to switchthe cam 70 to the second mode M2 when the automatic opening function isperformed based on the first mode M1 in the manual lock state, and themotor 60 is driven again in the second rotational direction c1 to bereturned to the first mode M1.

Further, the motor 60 is driven in the second rotational direction c1 toswitch the cam to the third mode M3 when the secure lock function isperformed based on the first mode M1 in the manual locked state, and themotor 60 is driven again in the first rotational direction c2 to bereturned to the first mode M1.

According to the above-described control method, the position of thelatch position adjusting profile 73 in contact with the contact surfaceof the latch 50 is only within a contact range R of FIG. 14. Based onthis principle, According to the embodiment, in an initial operation ofthe cooking device, assuming the position of the cam 70 is in the fourthmode in which the two switches are not pressed, the cam 70 is rotated inthe second rotational direction c2 in order to determine the initialpositions of the cam 70 and the latch 50.

When the cam 70 is in the fourth mode in the normal operation range R,the position of the cam 70 in contact with the latch 50 is between thethird mode and the first mode of FIG. 14 (between about 120° and 240°),and between the first mode and the second mode (about 260° to 370° (10°.Therefore, when the cam 70 is rotated in the second rotational directionc2, the cam 70 reaches the third mode or reaches the first mode, butdoes not reach the second mode. Therefore, when the cam 70 is rotated inthe second rotational direction c2, the door does not in the initialposition search step.

Geometrically, a position range in which the cam 70 does not press boththe switches are three cases, for example, a first case in which thesecond pressing boss 722 is within the angle of the two switches asshown in FIG. 15, a second case in which the first pressing boss 721 iswithin the angle of the two switches as shown in FIG. 16, and a thirdcase in which the two pressing bosses 721 and 722 deviate from the angleof the two switches as shown in FIG. 17.

Among these cases, the state as shown in FIG. 15 may be between thesecond mode and the first mode (between about 260° to 370° (10°)) ofFIG. 14. The state as shown in FIG. 16 may be the case where the cam isin the first mode and the third mode (about 120° to 240°).

Specifically, if the cam was initially in the position shown in FIG. 15,the cam reaches the first mode M1 after the cam is rotated in the secondrotational direction c2 for searching the initial position of the cam.The controller 80 stops driving the motor 60 when the two switches 81,82 are pressed. The cam 70 and the latch 50 are disposed in the manuallocked state.

If the cam 70 is initially in the position shown in FIG. 16, the cam 70reaches the third mode M3 after the cam is rotated in the secondrotational direction c2 for searching the initial position of the cam.As the third mode is the secure lock position, the door is notautomatically opened. When the second switch 82 is pressed and the firstswitch 81 is not pressed, the controller drives the motor 60 again inthe opposite direction to rotate the cam in the first rotationaldirection c1. The cam reaches the first mode M1. The controller stopsdriving the motor 60 when both switches 81, 82 are pressed. The cam andlatch may be in the manually locked position.

That is, within a normal operating range R, case 1 and case 2 as shownin FIG. 18 are provided as an example of searching an initial positionof the cam 70. Therefore, the door may not be automatically openedduring search of the cam 70 with respect to the initial position.

However, it may not exclude that the position of the cam 70 is in thestate shown in FIG. 17. For example, the initial position of the camduring manufacturing of the latch module 4 may be in the state as shownin FIG. 17. According to the embodiment, the controller 80 causes thecam 70 to rotate in the second rotational direction c2 when the cam isin the fourth mode during the initial driving of the cooking device. Ifthe cam rotates in the second rotational direction c2 and reaches thesecond mode M2, that is, if the first switch 81 is only pressed and thesecond switch 82 is not pressed, the cam is further rotated in thesecond rotational direction c2 as shown in case 3 in FIG. 18. As aresult, the cam enters the first mode M1. The controller stops thedriving the motor 60 when both switches 81, 82 are pressed. The cam andlatch may be in the manually locked position.

In such a state, the door may be opened. However, when the power issupplied to the latch module 4 before the latch module 4 is installed inthe cooking device during the manufacturing of the product, the cam 70and the latch 50 become the first mode M1 through the initial searchstep as described above. Further, during the manufacturing of theproduct, when the latch module 4 is installed in the cooking device andthe power is supplied to the cooking device for inspection of thecooking device, the above-described initial search step is performed andthe cam and the latch are in the first mode M1. Therefore, when theconsumer purchases the cooking device and first uses the cooking device,the cam may not be in the state as shown in FIG. 17.

FIG. 19 is block diagram of an electronic system to implement anautomatic opening structure and the control method as described aboveaccording to an embodiment of the invention. The electronic systemincludes, but not limited to, controller 80, the input device 100, suchas a touch panel, the display 90, switches 81, 82, the temperaturesensor 85, and the door sensor 88. The display 90 may display time,various operation status of the home appliance, and the like. The inputdevice 100 may be used to input instructions pertaining to the operationof the cooking device and the like. The controller 80 receives varioussignals and instructions and controls the cooking device based on thereceived signals and instructions. For instance, the controller 80 mayreceive instructions from the input device 100. The controller 80 mayreceive signals from the switches 81, 82, the door sensor 88, and thetemperature sensor 85. The controller 80 may control the motor 60 todrive the cam 70, which in turn interacts with the latch 50.

As described above, the controller 80 may control the position of thelatch 50 by controlling the rotational displacement of the cam 70through the switches 81 and 82 and the motor 60. In other words, thecontroller 80 may control such that the position of the latch 50 is atleast one of the first basic position, the second basic position (theautomatic opening position) and the third basic position (the securelock position). Further, as described above, the control as shown inFIG. 18 may also be possible through the controller 80.

The controller may be a microprocessor, specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), and the like.

While the present disclosure has been described with reference toexemplary embodiments thereof, it is to be understood that thedisclosure is not limited to the disclosed embodiments and drawings, andit will be apparent that various modifications may be made by thoseskilled in the art within the range of the technical idea of the presentdisclosure. For example, in the embodiment of the present disclosure, astructure in which a cam is applied as a power transmitting portion isexemplified, but a power transmission structure that adjusts a basicposition of the latch is implemented through a combination of variousother kinematic structures such as a long hole, a hinge, and a link, andthe like.

While the present disclosure does not explicitly describe the workingeffects based on the configuration of the present disclosure in thedescription of the embodiments of the present disclosure, it is to benoted that the expectable effects are acknowledged based on theconfiguration.

1-20. (canceled)
 21. A latch module for controlling an opening and aclosing of a door of an appliance, comprising: a latch engaged with orreleased from a engaging structure provided on the door; a cam thatcontacts a contact surface of the latch; and a motor that is coupled tothe cam and drives the cam to pivot the latch; wherein the latch havepositions comprising a first basic position, a second basic position,and a third basic position, wherein the first basic position is aposition in which the latch is engaged with the engaging structure tomaintain a closed state of the door and allows the door to be opened andclosed manually, wherein the second basic position is a position inwhich the latch is not engaged with the engaging structure, wherein thethird basic position is a position in which the latch is engaged withthe engaging structure to maintain a closed state of the door and thelatch securely locks the door and does not allow the door to be openedmanually.
 22. The latch module of claim 21, wherein, in the second basicposition, the latch is pivoted in a first direction with respect to thefirst basic position, and in the third basic position, the latch ispivoted in a second direction different from the first direction withrespect to the first basic position.
 23. The latch module of claim 21,wherein, the cam includes a first radius, a second radius, and a thirdradius in a circumferential direction at an outer circumference of thecam, the first radius of the cam interacts with the contact surface ofthe latch so that the latch is disposed in the first basic position, thesecond radius of the cam interacts with the contact surface of the latchso that the latch is disposed in the second basic position, and thethird radius of the cam interacts with the contact surface of the latchso that the latch is disposed in the third basic position.
 24. The latchmodule of claim 23, wherein, the second radius has a radius to pivot thelatch in a first direction with respect to the first basic position sothat the latch is disposed in the second basic position, and the thirdradius has a radius to pivot the latch in a second direction withrespect to the first basic position so that the latch is disposed in thethird basic position.
 25. The latch module of claim 23, wherein, thefirst radius is in a range of 210° to 320° with respect to a referenceline passing through a center of the cam and having 0°, the secondradius is in a range of 10° to 30°, and the third radius is in a rangeof 80° to 140°.
 26. The latch module of claim 23, wherein, the latchcomprises an extension having a sub-contact surface protruding from theextension in a direction of the cam, a cam surface facing thesub-contact surface with the first radius of the cam that contacts thecontact surface of the latch has a radius providing a space between thecam surface and the sub-contact surface that allows for the sub-contactsurface to approach the cam surface when the latch is moved from thefirst basic position to the second basic position.
 27. The latch moduleof claim 26, wherein, a distance between the sub-contact surface and acenter of rotation of the cam with the second radius of the cam thatcontacts the contact surface of the latch in the second basic positionis equal to or greater than a radius of the cam surface that faces thesub-contact surface.
 28. The latch module of claim 26, wherein, the camsurface that faces the sub-contact surface is the first radius, thethird radius or a connecting surface that connects the first radius andthe third radius when the first radius of the cam contacts the contactsurface of the latch.
 29. The latch module of claim 26, wherein, thesub-contact surface faces the first radius of the cam when the secondradius of the cam contacts the contact surface of the latch.
 30. Thelatch module of claim 26, wherein, the sub-contact surface does notinteract with the surface of the cam while a contact between the cam andthe contact surface of the latch transitions from the first radius tothe second radius when the cam is rotated.
 31. The latch module of claim26, wherein, the cam surface that faces the sub-contact surface is thesecond radius when the third radius of the cam contacts the contactsurface of the latch.
 32. The latch module of claim 26, wherein, theradius of the cam surface that faces the sub-contact surface with thethird radius of the cam in contact with the contact surface of the latchis greater than a distance between the sub-contact surface and thecenter of rotation of the cam when the latch is in the first basicposition.
 33. The latch module of claim 26, wherein, a radius of the camsurface that faces the sub-contact surface while a contact between thecam and the contact surface of the latch transitions from the firstradius to the third radius when the cam rotates exceeds the distancebetween the sub-contact surface and the center of rotation of the camwhen the latch is in the first basic position.
 34. The latch module ofclaim 33, wherein, the radius of the cam surface in contact with thesub-contact surface with the third radius of the cam contacting thecontact surface of the latch is the same as a distance between thesub-contact surface and the center of rotation of the cam forcing thelatch to be in the third basic position.
 35. The latch module of claim22, further comprising: an elastic body that applies a force to move thelatch in the first direction, and a drive that provides power to movethe latch in the second direction, wherein the cam transmits the powerof the drive to the latch, the elastic body and the cam move the latchto the first basic position, the second basic position in which thelatch is moved in the second direction from the first basic position,and the third basic position in which the latch is moved in the firstdirection from the first basic position.
 36. An appliance comprising: amain body including a cavity having an open front; a pull-down door thatopens and closes the open front of the cavity; a pin; a latch holderincluding; a latch to engage the pin; a bi-directional motor; and a camthat contacts a contact surface of the latch and is coupled to thebi-directional motor; wherein the latch is pivoted by the rotation ofthe cam, wherein the latch have positions comprising a first basicposition, a second basic position, and a third basic position, whereinthe first basic position is a position in which the latch is engagedwith the engaging structure to maintain a closed state of the door andallows the door to be opened and closed manually, wherein the secondbasic position is a position in which the latch is not engaged with theengaging structure, wherein the third basic position is a position inwhich the latch is engaged with the engaging structure to maintain aclosed state of the door and the latch securely locks the door and doesnot allow the door to be opened manually.
 37. The appliance of claim 36,wherein, the cam includes a first radius, a second radius, and a thirdradius in a circumferential direction at an outer circumference of thecam, the first radius of the cam interacts with the contact surface ofthe latch so that the latch is disposed in the first basic position, thesecond radius of the cam interacts with the contact surface of the latchso that the latch is disposed in the second basic position, and thethird radius of the cam interacts with the contact surface of the latchso that the latch is disposed in the third basic position.
 38. Theappliance of claim 37, wherein, the second radius is greater than thefirst radius, the third radius is less than the radius of the firstradius, the cam is rotated from the first radius to the third radius inan automatic opening operation, and the cam is rotated from first radiusto the second radius in a secure lock operation.
 39. The appliance ofclaim 37, wherein, the latch comprises an extension having a sub-contactsurface protruding from the extension in the direction of the cam, a camsurface facing the sub-contact surface with the first radius of the camthat contacts the contact surface of the latch has a radius providing aspace between the cam surface and the sub-contact surface that allowsfor the sub-contact surface to approach the cam surface when the latchis moved from the first basic position to the second basic position. 40.The appliance of claim 37, wherein, the radius of the cam surface thatfaces the sub-contact surface with the third radius of the cam incontact with the contact surface of the latch is greater than a distancebetween the sub-contact surface and the center of rotation of the camwhen the latch is in the first basic position.